In the field of intermittent drive continuously variable transmissions (CVT's) overrunning clutches such as sprag clutches or the like are frequently used to combine the outputs of multiple CVT stages which are driven from a common input. The major disadvantage of using any type of one-way clutch in a CVT is the inability of the transmission machines to perform engine braking (the transmission of power in both directions through the CVT). Typical examples of such machines are those described in the specifications of U.S. Pat. No. 6,425,301 and WO 82/02233.